阅读说明：本技术 一种电动处理渣浆过程除氯气方法 (Chlorine gas removing method in electric slag slurry treatment process ) 是由 黄新 刘钟 文磊 王鼎 张楚福 吕美东 于 2021-11-03 设计创作，主要内容包括：本发明涉及环境工程技术领域,尤其涉及一种电动处理渣浆过程除氯气方法,该方法对大体量高含水率碱渣渣浆同时除氯脱水,并对其中的有害氯化物选择有害氯离子进行清除而保留有益的钙离子,从而减少了需清除物质的总量,提高了清除效率提高了废渣资源化利用率；而且,本发明解决了电动技术用于碱渣渣浆除污存在的阳极附近产生氯气污染的问题。(The invention relates to the technical field of environmental engineering, in particular to a chlorine gas removal method in an electric slag slurry treatment process, which simultaneously removes chlorine and dehydrates large-volume high-water-content alkaline slag slurry, and selects harmful chloride ions to remove harmful chloride ions in the alkaline slag slurry to retain beneficial calcium ions, thereby reducing the total amount of substances to be removed, improving the removal efficiency and improving the resource utilization rate of waste slag; moreover, the invention solves the problem of chlorine pollution near the anode in the process of using the electric technology for removing the dirt of the alkaline residue slurry.)

1. A chlorine gas removing method in the process of electrically treating slag slurry is characterized by comprising the following steps: arranging a plurality of anode electrodes and a plurality of cathode electrodes in the caustic sludge slurry at intervals in parallel according to a given arrangement mode, wherein in the slurry, at least one cathode electrode is arranged around each anode electrode, and at least one anode electrode is arranged around each cathode electrode; a plurality of anode electrodes form an anode electrode group (1), and a plurality of cathode electrodes form a cathode electrode group (2); connecting the anode electrode to the positive pole of a direct current power supply, and connecting the cathode electrode to the negative pole of the direct current power supply; simultaneously connecting each anode electrode to a suction pipeline (4) connected with a vacuum negative pressure source (52), and communicating each cathode electrode with the atmosphere; applying an electric field to the slurry through the electrode according to the designed given power supply parameters, starting a vacuum negative pressure source (52) at the designed given time, and applying negative pressure to the slurry according to the designed given negative pressure supply parameters; carrying out negative pressure dehydration and electric dechlorination on the slurry;

under the combined action of the electric field and the negative pressure, chloride ions in the slurry migrate to the anode electrode and are discharged from a suction pipeline (4) connected with a vacuum negative pressure source (52); because the electromigration rate of the calcium ions is far higher than the liquid flow migration rate, the calcium ions are driven by an electric field to move to the cathode by countercurrent flow, and because the cathode has no outlet, the calcium ions are left in the caustic sludge; meanwhile, the moisture in the slurry is discharged from the suction pipeline (4) through the anode under the negative pressure drive;

the suction pipeline (4) is connected with the gas-liquid separation system, and a gas-liquid mixture containing chlorine is discharged through the suction pipeline (4), enters the gas-liquid separation system and is subjected to absorption treatment through the gas-liquid separation system.

2. The method for removing chlorine gas in the electric slag slurry treatment process according to claim 1, wherein for the slag slurry stored in the alkali slag storage, the anode electrode and the cathode electrode are vertically implanted into the slag slurry according to the designed depth, then a sealing film (6) is laid on the top surface of the slag slurry to isolate the system formed by the slag slurry and the electrodes from the atmosphere, and then an electric field and negative pressure are applied to carry out negative pressure dehydration and electric chlorine removal on the slag slurry.

3. The method for removing chlorine gas in the electric slag slurry treatment process according to claim 1, wherein for the incremental slag slurry discharged from the production line, a plurality of anode electrodes and a plurality of cathode electrodes are horizontally and parallelly arranged to form electrode layers; stacking the electrode layer and the slag slurry layer (3) with the given thickness alternately and successively in the enclosing barrier body according to the given stacking rate until reaching the designed stacking height; meanwhile, an electric field and negative pressure are applied to each slag slurry layer (3) layer by layer for negative pressure dehydration and electric dechlorination.

4. The method for removing chlorine gas in the electric treatment process of the slurry according to claim 1, wherein the anode electrode is a synchronous co-pressure water absorption electrode which can make liquid pass through and can apply negative pressure water absorption in the whole length range of the anode electrode at the synchronous co-pressure; the cathode electrode is an electrode which can conduct electricity and water and can release hydrogen generated at the cathode.

5. The method of claim 4, wherein the synchronous co-pressure water-absorbing electrode is a conductive material tube with a plurality of micropores on a tube wall, and the outer surface of the conductive material tube is coated with a filter layer.

6. The method for removing chlorine gas in the electric slag and slurry treatment process according to claim 4, wherein the synchronous and synchronous water absorption electrode comprises a water guide pipeline (11) and a strip (12); the pipe wall of the water guide pipe (11) is provided with a plurality of water outlet holes (110) which are arranged at intervals; each water outlet hole (110) on the pipe wall of the water guide pipeline (11) is connected with the strip (12), a plurality of parallel grooves (121) are arranged on the strip (12), and the port of each groove (121) is respectively communicated with one water outlet hole (110) on the pipe wall of the water guide pipeline (11); the strip (12) is made of conductive material, and the outer surface of the conductive strip (12) is coated with a filter layer.

7. The method for removing chlorine gas in the electric slag and slurry treatment process according to claim 6, wherein the synchronous and pressure water absorption electrode is used for vertical planting and further comprises a suction pipe (10); the two ends of the water guide pipeline (11) are sealed, the suction pipe (10) is arranged in the water guide pipeline (11), a gap is formed between one end of the suction pipe (10) and the bottom end of the water guide pipeline (11), the top end face of the water guide pipeline (11) is penetrated by the top end of the suction pipe (10), and the pipe wall of the suction pipe (10) at the position where the top end face of the water guide pipeline (11) is penetrated is sealed with the top end face of the water guide pipeline (11) in an airtight mode.

8. The method for removing chlorine gas in the electric slag slurry treatment process according to claim 1, wherein the gas-liquid separation system comprises a liquid storage tank device (51), a vacuum negative pressure source (52) and a gas pressure reduction tank device (53); one end of the suction pipeline (4) is connected to the liquid storage tank device (51), and a first liquid level sensor (511) is arranged on the liquid storage tank device (51); a first liquid pump pumping pipeline (512) is arranged at the bottom of the liquid storage tank device (51); the liquid storage tank device (51) is connected with the air inlet end of the vacuum negative pressure source (52) through a first connecting pipe, and the air outlet end of the vacuum negative pressure source (52) is connected with the gas pressure reduction tank device (53) through a second connecting pipe; the gas decompression tank device (53) is provided with a second liquid level sensor (531); a second liquid pump pumping pipeline (532) is arranged at the bottom of the gas pressure reduction tank device (53); a plurality of spraying pipes (533) are arranged at the upper part of the gas pressure reduction tank device (53), and the liquid inlet ends of the spraying pipes (533) are communicated with the liquid supply pool; the liquid outlet end of the spraying pipe (533) is provided with a spraying head; the top of the gas pressure reduction tank device (53) is also provided with a chlorine absorption pipeline (534), and the chlorine absorption pipeline (534) is respectively connected with the atmosphere and the chlorine absorption device; and an atmosphere switch (535) and a chlorine absorption switch (536) are respectively arranged on the chlorine absorption pipeline (534).

9. The method for removing chlorine gas in the electric slag and slurry treatment process according to claim 8, wherein the chlorine-containing gas discharged through the suction pipeline (4), subjected to gas-liquid separation and then introduced into the gas pressure reduction tank device (53) is treated by the following measures according to specific conditions;

firstly, the chlorine content in the gas does not exceed the limit value of the national environmental protection standard, and the gas is directly discharged to the atmosphere;

secondly, spraying liquid mist for absorbing chlorine from a spraying pipe (533) at the upper part of the gas pressure reduction tank device (53) when the chlorine content in the gas exceeds the limit value of the national environmental protection standard, and discharging the gas to the atmosphere if the chlorine content of the treated gas does not exceed the limit value of the national environmental protection standard;

and thirdly, if the chlorine content in the gas still exceeds the national atmosphere environmental protection standard after the treatment by the method, pumping the gas out of a chlorine absorption pipeline (534) at the top of the gas pressure reduction tank device (53) by using a gas pump and treating the gas according to a known chlorine absorption method.

10. The method for removing chlorine gas in the electric slag slurry treatment process according to claim 9, wherein the implementation mode comprises the following steps:

(i) slurry discharged from the production line:

1) constructing a slag slurry baffle at the periphery of a site where slag slurry is to be piled;

2) arranging the cathode electrodes and the anode electrodes in parallel according to a given arrangement mode, a given interval and a given horizontal direction to form an electrode layer;

3) in the enclosure, alternately stacking the electrode layer and the slag slurry layer (3) layer by layer according to a designed and given stacking rate until a designed and given stacking height is reached; in the slag slurry layer (3), at least one cathode electrode is arranged around each anode electrode, and at least one anode electrode is arranged around each cathode electrode;

4) meanwhile, the following work is finished layer by layer from the bottom slag slurry layer (3) to the top: connecting each electrode in an anode electrode group (1) in the slag slurry layer (3) with the positive electrode of a direct current power supply, and connecting each electrode in a cathode electrode group (2) in the slag slurry layer (3) with the negative electrode of the direct current power supply; simultaneously, each electrode in the anode electrode group (1) is connected with a suction pipeline (4) connected with a vacuum negative pressure source (52), and each electrode in the cathode electrode group (1) is communicated with the atmosphere; turning on a power supply, applying an electric field to the slurry layer (3) according to the designed and given electric field parameters, turning on a vacuum negative pressure source (52) at the designed and given time, and applying negative pressure to the slurry layer (3) according to the designed and given negative pressure supply parameters; the slag slurry layer (3) is simultaneously subjected to negative pressure dehydration and electric dechlorination;

5) meanwhile, the following work is finished layer by layer from the bottom slag slurry layer (3) to the top: when the concentration and the water content of the chloride ions in the slag slurry layer (3) reach design given indexes, the connection with a vacuum negative pressure source (52) can be cut off, and the anode electrode of the slag slurry layer (3) is disconnected with a power supply; the chlorine removal and dehydration work of the slag slurry layer (3) is completed;

6) operating each slag slurry layer (3) layer by layer successively according to the methods and requirements of the steps 3) to 5) until all the piled slag slurry layers are built

The slag slurry layer (3) completes dechlorination and dehydration work;

(ii) for the stock slurry piled in the alkaline residue storage:

1) implanting the anode electrode and the cathode electrode into the slurry in a vertical parallel manner according to the designed given depth, arrangement mode, distance and direction; at least one cathode electrode is arranged around each anode electrode, and at least one anode electrode is arranged around each cathode electrode; a plurality of anode electrodes form an anode electrode group (1), and a plurality of cathode electrodes form a cathode electrode group (2); connecting each anode electrode with the positive electrode of a direct current power supply, and connecting each cathode electrode with the negative electrode of the direct current power supply; simultaneously connecting each anode electrode to a suction pipeline (4) connected with a vacuum negative pressure source (52), and connecting each cathode electrode with an exhaust branch pipe communicated with the atmosphere; then a closed film is laid on the top surface of the slurry,

isolating a system formed by the slurry and the electrode from the atmosphere;

2) turning on a power supply, applying an electric field to the slurry according to the designed and given electric field parameters, turning on a vacuum negative pressure source (52) at the designed and given time, and applying negative pressure to the slurry according to the designed and given negative pressure supply parameters; carrying out negative pressure dehydration and electric dechlorination on the slurry;

3) when the concentration and the water content of the chloride ions in the slurry reach design given indexes, the vacuum negative pressure source (52) and the power supply can be closed; the chlorine removal and dehydration work of the slag slurry layer (3) is completed;

(iii) because the anode is communicated with the vacuum negative pressure source (52), the anode is in a basically anhydrous state, and chlorine is generated after chloride ions driven to the anode by an electric field are contacted with a naked electric conductor in the anode; the gas-liquid mixture containing the chlorine is drawn by a vacuum negative pressure source (52) and is discharged through a suction pipeline (4); the liquid is deposited in a liquid storage tank device (51) and is pumped by a first liquid pump pumping pipeline (512) and discharged into a liquid storage tank; the gas is discharged into a gas decompression tank device (53) through a vacuum negative pressure source (52); then, according to specific situations, the following measures are respectively adopted:

firstly, the chlorine content in the gas does not exceed the limit value of the national environmental protection standard, and the gas is directly discharged to the atmosphere;

secondly, spraying liquid mist for absorbing chlorine from a spraying pipe (533) at the upper part of the gas pressure reduction tank device (53) when the chlorine content in the gas exceeds the limit value of the national environmental protection standard, and discharging the gas to the atmosphere if the chlorine content of the treated gas does not exceed the limit value of the national environmental protection standard;

thirdly, if the chlorine content in the gas is still higher than the national atmosphere environmental protection standard after the treatment by the method in ii), the gas is pumped out by a gas pump through a chlorine absorption pipeline (534) at the top of the gas pressure reduction tank device (53) and is treated according to the known chlorine absorption method.

Technical Field

The invention relates to the technical field of environmental engineering, in particular to a chlorine gas removing method in an electric slag slurry treatment process.

Background

The caustic sludge slurry is high-water-content waste sludge slurry discharged in the production of soda ash, and 300 kg of dry-based waste sludge is discharged in each ton of soda ash production. At present, no suitable technology for utilizing the alkaline residue slurry exists in the world, and the alkaline residue slurry is basically piled in a residue slurry warehouse; the accumulated caustic sludge slurry pollutes the environment, the storage capacity of the slurry is limited, so the accumulation method is not sustainable, and enterprises cannot bear huge cost consumption caused by accumulation and storage of the caustic sludge slurry continuously generated in subsequent production. The main component of the alkaline residue slurry is CaCO₃And a part of CaCl₂Are isolyotropic salts. Calcium carbonate in the alkaline residue slurry can be used as a raw material of a plurality of industries, but the chlorine salt contained in the alkaline residue slurry is a main problem which hinders the resource utilization of the alkaline residue slurry. At present, no practical technology with acceptable cost performance is available, which can be suitable for dechlorinating the large-volume caustic sludge slurry. The caustic sludge slurry of the caustic plant is usually discharged from a high-water-content waste sludge and stored in a caustic sludge slurry warehouse intercepted by a dam body. In order to carry out harmless treatment or resource utilization on the caustic sludge slurry, the caustic sludge slurry needs to be dehydrated; but at present, no proper dehydration method for large-volume waste residues exists; although the existing technologies such as mechanical filter pressing, centrifugal dehydration, drying dehydration and the like are used, the processing cost of the dehydration technologies is too high, and huge economic burden is added to enterprises. Some alkali factories can discharge dozens of thousands of tons of basic waste slag every year, and the amount of the basic waste slag pulp piled in the basic waste slag pulp storehouse is as high as thousands of cubic meters.

Other industries also discard CaCO as the main component₃And contains CaCl₂Waste residue slurry with high water content and easily soluble chlorine salt, such as saponified waste residue generated in propylene oxide production, filter mud discarded by sugar industry, and caustic white mud discarded by paper industry.

Theoretically, when a dc electric field is applied to the wet caustic sludge slurry, the soluble ions of the salt and alkali in the caustic sludge slurry migrate to the electrode with the opposite electrical property, and are removed from the waste residue. However, the adoption of the electric technology based on the principle to remove chlorine from the alkaline residue slurry faces a plurality of problems: 1) the chloride ions migrating to the electrode will form chlorine gas, pairAir can cause serious pollution; the problem of chlorine is solved, namely the prerequisite condition whether the electric technology can be adopted to carry out dechlorination on the alkaline residue slurry is solved; 2) if chlorine is removed by conventional electrokinetic techniques, CaCl₂Chloride ions and calcium ions formed after being dissolved in water can be completely removed; but the harmful components are only chloride ions, and calcium ions are not only harmless, but also ions required for subsequent resource utilization; if only chloride ions can be removed and calcium ions are reserved, the removal cost is reduced and the removal amount is reduced, and the beneficial substance remaining amount is increased; 3) in addition, in order to perform harmless treatment or resource utilization on the caustic sludge slurry with high water content, the caustic sludge slurry needs to be dehydrated; but the electrokinetic technique cannot dewater the caustic sludge.

Disclosure of Invention

The invention aims to solve the technical problem that the slag slurry contains chloride and has high water content to prevent resource utilization of the slag slurry, and provides a slag slurry dechlorination and dehydration method for the alkaline slag slurry with large volume and high water content, which has no chlorine pollution and can only remove chloride ions and retain calcium ions.

For the purpose of the invention, the following technical scheme is adopted for realizing the purpose:

a chlorine gas removing method in an electric slag slurry treatment process comprises the following steps: arranging a plurality of anode electrodes and a plurality of cathode electrodes in the caustic sludge slurry at intervals in parallel according to a given arrangement mode, wherein in the slurry, at least one cathode electrode is arranged around each anode electrode, and at least one anode electrode is arranged around each cathode electrode; the plurality of anode electrodes form an anode electrode group, and the plurality of cathode electrodes form a cathode electrode group; connecting the anode electrode to the positive pole of a direct current power supply, and connecting the cathode electrode to the negative pole of the direct current power supply; meanwhile, connecting each anode electrode to a suction pipeline connected with a vacuum negative pressure source, and communicating each cathode electrode with the atmosphere; applying an electric field to the slurry through an electrode according to the designed given power supply parameters, starting a vacuum negative pressure source at the designed given time, and applying negative pressure to the slurry according to the designed given negative pressure supply parameters; carrying out negative pressure dehydration and electric dechlorination on the slurry;

under the combined action of the electric field and the negative pressure, chloride ions in the slurry migrate to the anode electrode and are discharged from a suction pipeline connected with a vacuum negative pressure source; because the electromigration rate of the calcium ions is far higher than the liquid flow migration rate, the calcium ions are driven by an electric field to move to the cathode by countercurrent flow, and because the cathode has no outlet, the calcium ions are left in the caustic sludge; simultaneously, water in the slurry is discharged from the suction pipeline through the anode under the negative pressure drive;

the suction pipeline is connected with the gas-liquid separation system, and a gas-liquid mixture containing chlorine is discharged through the suction pipeline, enters the gas-liquid separation system and is subjected to absorption treatment through the gas-liquid separation system.

Preferably, for the stored slurry stored in the alkaline residue storage, the anode electrode and the cathode electrode are vertically implanted into the slurry according to the designed given depth, then a sealing film is laid on the top surface of the slurry, a system formed by the slurry and the electrode is isolated from the atmosphere, and then an electric field and negative pressure are applied to carry out negative pressure dehydration and electric dechlorination on the slurry.

Preferably, for incremental slurry discharged from a production line, a plurality of anode electrodes and a plurality of cathode electrodes are horizontally and parallelly arranged to form an electrode layer; stacking the electrode layer and the slag slurry layer with the designed given thickness in the enclosing barrier body alternately and successively according to the designed given stacking rate until reaching the designed stacking height; and meanwhile, applying an electric field and negative pressure to each slurry layer by layer for negative pressure dehydration and electric dechlorination.

Preferably, the anode electrode is a synchronous co-pressure water absorption electrode which can pass liquid and can apply negative pressure water absorption in the whole length range of the anode electrode at the synchronous co-pressure; the cathode electrode is an electrode which can conduct electricity and water and is used for releasing hydrogen generated at the cathode.

Preferably, the synchronous and synchronous water absorption electrode is a conductive material pipe with a plurality of micropores on the pipe wall, and the outer surface of the conductive material pipe is coated with a filter layer.

Preferably, the synchronous and synchronous water absorption electrode comprises a water guide pipeline and a strip; a plurality of water outlet holes which are arranged at intervals are arranged on the pipe wall of the water guide pipeline; each water outlet hole on the pipe wall of the water guide pipeline is connected with the strip, a plurality of parallel grooves are arranged on the strip, and the port of each groove is communicated with one water outlet hole on the pipe wall of the water guide pipeline; the strip is made of conductive material, and the outer surface of the conductor strip is coated with a filter layer.

Preferably, when the synchronous and synchronous pressure water absorption electrode is used for vertical implantation, the synchronous and synchronous pressure water absorption electrode also comprises a suction tube; the two ends of the water guide pipeline are closed, the suction pipe is arranged in the water guide pipeline, a gap is arranged between one end of the suction pipe and the bottom end of the water guide pipeline, the top end of the suction pipe penetrates through the top end face of the water guide pipeline, and the pipe wall of the suction pipe penetrating through the top end face of the water guide pipeline is hermetically closed with the top end face of the water guide pipeline.

Preferably, the gas-liquid separation system comprises a liquid storage tank device, a vacuum negative pressure source and a gas pressure reduction tank device; one end of the suction pipeline is connected to the liquid storage tank device, and a first liquid level sensor is arranged on the liquid storage tank device; a first liquid pump pumping pipeline is arranged at the bottom of the liquid storage tank device; the liquid storage tank device is connected with the air inlet end of the vacuum negative pressure source through a first connecting pipe, and the air outlet end of the vacuum negative pressure source is connected with the gas pressure reduction tank device through a second connecting pipe; the gas pressure reduction tank device is provided with a second liquid level sensor; a second liquid pump pumping pipeline is arranged at the bottom of the gas pressure reduction tank device; the upper part of the gas pressure reduction tank device is provided with a plurality of spraying pipes, and the liquid inlet ends of the spraying pipes are communicated with the liquid supply pool; the liquid outlet end of the spraying pipe is provided with a spraying head; the top of the gas pressure reduction tank device is also provided with a chlorine absorption pipeline which is respectively connected with the atmosphere and the chlorine absorption device; and an atmosphere switch and a chlorine absorption switch are respectively arranged on the chlorine absorption pipeline.

Preferably, the chlorine-containing gas discharged through the suction pipeline, subjected to gas-liquid separation and then introduced into the gas pressure reduction tank device is treated by the following measures according to specific conditions;

firstly, the chlorine content in the gas does not exceed the limit value of the national environmental protection standard, and the gas is directly discharged to the atmosphere;

secondly, spraying liquid mist for absorbing chlorine from a spraying pipe at the upper part of the gas pressure reduction tank device if the chlorine content in the gas exceeds the limit value of the national environmental protection standard, and discharging the gas to the atmosphere if the chlorine content of the treated gas does not exceed the limit value of the national environmental protection standard;

and thirdly, if the chlorine content in the gas still exceeds the national atmosphere environmental protection standard after the treatment by the method, pumping the gas out of a chlorine absorption pipeline at the top of the gas pressure reduction tank device by using a gas pump, and treating the gas according to a known chlorine absorption method.

Preferably, the method comprises the following steps:

(i) slurry discharged from the production line:

1) constructing a slag slurry baffle at the periphery of a site where slag slurry is to be piled;

2) arranging the cathode electrodes and the anode electrodes in parallel according to a given arrangement mode, a given interval and a given horizontal direction to form an electrode layer;

3) in the enclosure, alternately stacking the electrode layers and the slurry layers layer by layer according to a designed and given stacking rate until a designed and given stacking height is reached; in the slurry layer, at least one cathode electrode is arranged around each anode electrode, and at least one anode electrode is arranged around each cathode electrode;

4) meanwhile, the following work is finished layer by layer from the bottom slag slurry layer to the top layer: connecting each electrode in the anode electrode group in the slag slurry layer with the positive electrode of a direct current power supply, and connecting each electrode in the cathode electrode group in the slag slurry layer with the negative electrode of the direct current power supply; meanwhile, each electrode in the anode electrode group is connected with a suction pipeline connected with a vacuum negative pressure source, and each electrode in the cathode electrode group is communicated with the atmosphere; turning on a power supply, applying an electric field to the slurry layer according to the designed and given electric field parameters, turning on a vacuum negative pressure source at the designed and given time, and applying negative pressure to the slurry layer according to the designed and given negative pressure supply parameters; carrying out negative pressure dehydration and electric dechlorination on the slag slurry layer simultaneously;

5) meanwhile, the following work is finished layer by layer from the bottom slag slurry layer to the top layer: when the concentration and the water content of the chloride ions in the slag slurry layer reach design given indexes, the connection with a vacuum negative pressure source can be cut off, and the anode electrode of the slag slurry layer is disconnected with a power supply; the work of dechlorination and dehydration of the slag slurry layer is completed;

6) operating each slurry layer by layer successively according to the methods and requirements of the steps 3) to 5) until all the slurry layers are built to finish dechlorination and dehydration;

(ii) for the stock slurry piled in the alkaline residue storage:

1) implanting the anode electrode and the cathode electrode into the slurry in a vertical parallel manner according to the designed given depth, arrangement mode, distance and direction; at least one cathode electrode is arranged around each anode electrode, and at least one anode electrode is arranged around each cathode electrode; the plurality of anode electrodes form an anode electrode group, and the plurality of cathode electrodes form a cathode electrode group; connecting each anode electrode with the positive electrode of a direct current power supply, and connecting each cathode electrode with the negative electrode of the direct current power supply; meanwhile, each anode electrode is connected with a suction pipeline connected with a vacuum negative pressure source, and each cathode electrode is connected with an exhaust branch pipe communicated with the atmosphere; then, a closed film is laid on the top surface of the slurry to isolate a system formed by the slurry and the electrode from the atmosphere;

2) turning on a power supply, applying an electric field to the slurry according to the designed and given electric field parameters, turning on a vacuum negative pressure source at the designed and given time, and applying negative pressure to the slurry according to the designed and given negative pressure supply parameters; carrying out negative pressure dehydration and electric dechlorination on the slurry;

3) when the concentration and the water content of the chloride ions in the slurry reach design given indexes, the vacuum negative pressure source and the power supply can be closed; the work of dechlorination and dehydration of the slag slurry layer is completed;

(iii) because the anode is communicated with the vacuum negative pressure source and is in a basically anhydrous state, chlorine is generated after chloride ions driven to the anode by the electric field are contacted with the exposed conductor in the anode; the gas-liquid mixture containing chlorine is drawn by a vacuum negative pressure source and is discharged through a suction pipeline; the liquid is deposited in a liquid storage tank device and is pumped out by a first liquid pump pumping pipeline and is discharged into a liquid storage tank; the gas is discharged into a gas pressure reduction tank device through a vacuum negative pressure source; then, according to specific situations, the following measures are respectively adopted:

firstly, the chlorine content in the gas does not exceed the limit value of the national environmental protection standard, and the gas is directly discharged to the atmosphere;

secondly, spraying liquid mist for absorbing chlorine from a spraying pipe at the upper part of the gas pressure reduction tank device if the chlorine content in the gas exceeds the limit value of the national environmental protection standard, and discharging the gas to the atmosphere if the chlorine content of the treated gas does not exceed the limit value of the national environmental protection standard;

thirdly, if the chlorine content in the gas is still higher than the national atmosphere environmental protection standard after the treatment by the method in ii), the gas is pumped out by a gas pump through a chlorine absorption pipeline at the top of the gas pressure reduction tank device and is treated according to the known chlorine absorption method.

By adopting the technical scheme, the method for removing chlorine gas in the process of electrically treating the slag slurry solves the problem that the large-volume high-water-content alkaline slag slurry has no economic and effective chlorine removal dehydration method; the method solves a technical obstacle encountered when the electric technology is used for removing the dirt of the specific substance of the alkaline residue slurry, namely harmful chlorine generated at the anode pollutes the environment; the technology can remove harmful chloride ions from the alkaline residue slurry and retain beneficial calcium ions, thereby reducing the total amount of substances to be removed, improving the removal efficiency and reducing the high cost of decontamination; meanwhile, more beneficial substances can be reserved, the resource utilization rate of the waste residues is improved, and the high-water-content alkaline residue slurry is dehydrated; not only can greatly reduce the volume of the waste residue and further reduce the occupied area of a waste residue storage yard, but also the harmless waste residue with pollutants removed can be recycled as industrial raw materials.

In conclusion, the method has the advantages that the method can simultaneously remove chlorine and dehydrate the alkaline residue slurry with large volume and high water content, and can remove harmful chloride ions from harmful chloride to retain beneficial calcium ions, thereby reducing the total amount of substances to be removed, improving the removal efficiency and improving the resource utilization rate of waste residues; moreover, the invention solves the problem of chlorine pollution near the anode in the process of using the electric technology for removing the dirt of the alkaline residue slurry.

Drawings

FIG. 1 is a schematic structural diagram of chlorine removal treatment (vertical direction) in the electric slurry treatment process of the invention.

FIGS. 2 to 5 are schematic structural views of chlorine removal treatment (horizontal direction) in the electric slurry treatment process of the present invention.

Fig. 6 is a schematic diagram of the structure of the synchronous water absorption electrode (vertical direction) in the invention.

Fig. 7 is a sectional view in the direction of a (vertical) axis of the synchronous simultaneous pressure water-absorbing electrode in fig. 6 according to the present invention.

Fig. 8 is a schematic structural diagram of the middle vertical water-permeable electrode of the invention.

FIG. 9 is a schematic view of the structure of a synchronous water-absorbing electrode (horizontal direction) in the present invention.

FIG. 10 is a schematic view of the structure of the synchronous water sucking electrode (horizontal direction) in the direction B in FIG. 9.

FIG. 11 is a schematic view showing the structure of a gas-liquid separation system in the present invention.

Wherein: 1. an anode electrode group; 10. a suction tube; 11. a water guide pipeline; 110. a water outlet hole; 12. a strip; 121. a groove; 14. an outer tube; 140. micropores; 142. a gap; 15. an inner tube; 151. a water outlet of the inner pipe; 101. a first layer of anode electrode groups; 102. a second layer of anode electrode groups; 103 a third layer of anode electrode groups; 2. a cathode electrode group; 201. a first layer of cathode electrode sets; 202. a second layer of cathode electrode assembly; 3. a slurry layer; 31. a first slurry layer; 32. a second slurry layer; 33. a third slurry layer; 34. a fourth slurry layer; 4. a suction duct; 51. a liquid storage tank device; 511. a first liquid level sensor; 512. a first liquid pump withdrawal line; 52. a vacuum negative pressure source; 53. a gas pressure reduction tank arrangement; 531. a second liquid level sensor; 532. a second liquid pump draws the tubing; 533. a spray tube; 534. a chlorine absorption pipeline; 535. an atmospheric switch; 536. a chlorine absorption switch; 6 sealing the film.

Detailed Description

The invention is further described with reference to the following figures and detailed description.

As shown in fig. 1 to 5, a chlorine removal method in an electric treatment process of slurry comprises arranging a plurality of anode electrodes and a plurality of cathode electrodes in parallel in the caustic sludge slurry at intervals according to a given arrangement mode, wherein in the slurry, at least one cathode electrode is arranged around each anode electrode, and at least one anode electrode is arranged around each cathode electrode; a plurality of anode electrodes form an anode electrode group 1, and a plurality of cathode electrodes form a cathode electrode group 2; connecting the anode electrode to the positive pole of a direct current power supply, and connecting the cathode electrode to the negative pole of the direct current power supply; simultaneously connecting each anode electrode to the suction pipe 4 connected to the vacuum negative pressure source 52, and connecting each cathode electrode to the atmosphere; applying an electric field to the slurry through the electrodes according to the designed given power supply parameters, starting the vacuum negative pressure source 52 at the designed given time, and applying negative pressure to the slurry according to the designed given negative pressure supply parameters; carrying out negative pressure dehydration and electric dechlorination on the slurry;

under the combined action of the electric field and the negative pressure, chloride ions in the slurry migrate to the anode electrode and are discharged from the suction pipeline 4 connected with the vacuum negative pressure source 52; because the electromigration rate of the calcium ions is far higher than the liquid flow migration rate, the calcium ions are driven by an electric field to move to the cathode by countercurrent flow, and because the cathode has no outlet, the calcium ions are left in the caustic sludge; meanwhile, the moisture in the slurry is discharged from the suction pipeline 4 through the anode under the negative pressure drive;

the suction pipeline 4 is connected with the gas-liquid separation system, and a gas-liquid mixture containing chlorine is discharged through the suction pipeline 4, enters the gas-liquid separation system and is subjected to absorption treatment through the gas-liquid separation system.

As shown in figure 1, the electrode is vertically arranged in the chlorine gas removal method in the electric slag slurry treatment process, for the slag slurry stored in an alkali slag warehouse, an anode electrode and a cathode electrode are vertically implanted into the slag slurry according to the designed given depth, then a sealing film 6 is laid on the top surface of the slag slurry, a system formed by a slag slurry layer 3 and the electrode is isolated from the atmosphere, and then an electric field and negative pressure are applied to carry out negative pressure dehydration and electric chlorine removal on the slag slurry.

The specific steps described above are:

1) implanting the anode electrode and the cathode electrode into the slurry in a vertical parallel manner according to the designed given depth, arrangement mode, distance and direction; at least one cathode electrode is arranged around each anode electrode, and at least one anode electrode is arranged around each cathode electrode; a plurality of anode electrodes form an anode electrode group 1, and a plurality of cathode electrodes form a cathode electrode group 2; connecting each anode electrode with the positive electrode of a direct current power supply, and connecting each cathode electrode with the negative electrode of the direct current power supply; meanwhile, each anode electrode is connected to the suction pipeline 4 connected with the vacuum negative pressure source 52, and each cathode electrode is connected with an exhaust branch pipe communicated with the atmosphere; then, a sealing film 6 is laid on the top surface of the slurry to isolate a system formed by the slurry and the electrode from the atmosphere;

2) turning on a power supply, applying an electric field to the slurry according to the designed and given electric field parameters, turning on the vacuum negative pressure source 52 at the designed and given time, and applying negative pressure to the slurry according to the designed and given negative pressure supply parameters; carrying out negative pressure dehydration and electric dechlorination on the slurry;

3) when the concentration and the water content of the chloride ions in the slurry reach design given indexes, the vacuum negative pressure source 52 and the power supply can be closed; the chlorine removal and dehydration of the slurry layer 3 are completed.

As shown in fig. 2 to 5, the electrode of the chlorine gas removal method in the electric treatment process of the slag slurry is horizontally arranged, and the alkaline slag slurry discharged from the production line is treated by the following steps:

firstly), constructing a slurry baffle at the periphery of a site where slurry is to be piled;

secondly), arranging the cathode electrode and the anode electrode in parallel according to a designed given arrangement mode, a given distance and a given horizontal direction to form an electrode layer;

thirdly), alternately stacking the electrode layer and the slurry layer 3 layer by layer in the enclosure body according to the designed and given stacking rate until the designed and given stacking height is reached; in the slurry layer 3, at least one cathode electrode is arranged around each anode electrode, and at least one anode electrode is arranged around each cathode electrode;

fourthly), the following work is finished layer by layer from the bottom slag slurry layer 3 to the top layer by layer: connecting each electrode in the anode electrode group 1 in the slag slurry layer 3 with the positive electrode of a direct current power supply, and connecting each electrode in the cathode electrode group 2 in the slag slurry layer 3 with the negative electrode of the direct current power supply; meanwhile, each electrode in the anode electrode group 1 is connected with a suction pipeline 4 connected with a vacuum negative pressure source 52, and each electrode in the cathode electrode group 1 is communicated with the atmosphere; turning on a power supply, applying an electric field to the slurry layer 3 according to the designed and given electric field parameters, turning on a vacuum negative pressure source 52 at the designed and given time, and applying negative pressure to the slurry layer 3 according to the designed and given negative pressure supply parameters; the slag slurry layer 3 is simultaneously subjected to negative pressure dehydration and electric dechlorination work;

fifthly), the following work is finished layer by layer from the bottom slag slurry layer 3 to the top: when the concentration and the water content of the chloride ions in the slurry layer 3 reach design given indexes, the connection with the vacuum negative pressure source 52 can be cut off, and the anode electrode of the slurry layer 3 is disconnected with a power supply; the chlorine removal and dehydration work of the slag slurry layer 3 is completed;

sixthly), operating each slag slurry layer 3 layer by layer according to the methods and requirements of the step three) to the step 5) until all the stacked slag slurry layers 3 finish dechlorination and dehydration;

the specific steps described above are:

the first step is as follows: estimating the possible stacking height of the alkaline residue slurry based on an earth slope stabilization theory or test in the field of geotechnical engineering according to the physical and mechanical properties of the alkaline residue slurry;

the second step is that: constructing a ring of enclosure body around a site where the slag slurry is to be piled, wherein the enclosure body can be a cofferdam constructed by alkali slag slurry with proper water content or solidified and transformed alkali slag slurry, and can also adopt enclosure technology in other modes; the technical requirements of the retaining body structure are estimated according to the soil slope stability theory or test based on the geotechnical engineering field;

the third step: arranging the electrodes horizontally in parallel according to a given arrangement mode to form an electrode layer; and in the enclosure body, the electrode layer and the slag slurry layer with the given thickness are alternately stacked layer by layer according to the given stacking speed until the given stacking height is designed. Based on the soil mechanics drainage consolidation theory of geotechnical engineering, under the action of pressure lower than the bearing capacity of a saturated soil body, water in the saturated soil body is squeezed out, so that the strength of the saturated soil body is improved, and higher pressure can be borne; if the pressure acting on the soil body is higher than the bearing capacity of the soil body, the soil body can be damaged. The designed given stacking rate is calculated according to a drainage consolidation theory and related test data, and the stable stacking rate of the lower-layer slurry can be guaranteed.

The arrangement mode of the electrodes in the slurry requires that at least one cathode electrode is arranged around each anode electrode, and at least one anode electrode is arranged around each cathode electrode;

electrode arrangement 1, which is convenient to implement, is: the electrodes on the same layer are all electrode groups formed by homopolar electrodes, and the anode electrode group layers and the cathode electrode group layers are arranged alternately, namely a layer of anode electrode group 1, a slag slurry layer 3, a layer of cathode electrode group 2, a slag slurry layer 3 and the like; each corresponding electrode of each electrode layer may be vertically aligned, i.e. arranged in a square; or the corresponding electrodes of the upper layer and the lower layer can be horizontally shifted and staggered by half a distance, namely, the electrodes are arranged in a triangular shape;

electrode arrangement 2, which is convenient to implement, is: each electrode layer is provided with an anode electrode group and a cathode electrode group, and the anode electrodes and the cathode electrodes are arranged alternately; the electrodes at the corresponding positions of the electrode layers are vertically aligned; the electrodes at the corresponding positions of each electrode layer can be the same-polarity electrodes, namely, a column of anode electrode groups 1, a column of slurry, a column of cathode electrode groups 2 and a column of slurry are shown in the vertical section, and the like; the electrodes at the corresponding positions of the electrode layers can also be anode electrodes and cathode electrodes which are arranged alternately, namely the electrodes are arranged alternately in the vertical and horizontal directions when viewed in a vertical section.

The arrangement direction of the electrodes in the electrode layer on the top surface of the slurry layer and the arrangement direction of the electrodes in the electrode layer on the bottom surface of the slurry layer may be the same or orthogonal to each other. The electrode layers arranged in the horizontal direction in the slurry are used for exerting an electric field and draining water, and can also play a role in transversely reinforcing the slurry, so that the stability of the slurry stacking body is facilitated; when the electrode layers are alternately and orthogonally arranged, the transverse reinforcing effect can be achieved on all aspects of the slag slurry piling body, and the lifting of the pile height of the slag slurry piling body is facilitated.

The implementation procedure of the electrode arrangement mode 1 is slightly different from that of the electrode arrangement mode 2, and the following description will be given only by taking the electrode arrangement mode 1 as a preferred embodiment, and a person skilled in the art can derive implementation procedures of other electrode arrangement modes by referring to the implementation procedures.

The fourth step: arranging a group of first layer anode electrode groups 101 consisting of synchronous and same-pressure water absorption electrodes which are arranged in parallel and horizontally at given intervals according to design on the bottom surface of an inner field of the slag slurry enclosure, injecting a first slag slurry layer 31 on the first layer anode electrode groups, and laying a first layer cathode electrode group 201 on the slag slurry layer 31; or the cathode electrode group 2 can be laid first, and then the anode electrode group 1 can be laid; alkaline residue slurry is injected on the first layer cathode electrode group 201 again to form a second residue slurry layer 32, but the fifth step can be carried out after the thickness of the injected residue slurry meets the requirement of protecting the electrode group;

the fifth step: connecting each electrode in the first layer anode electrode group 101 with the positive electrode of a direct current power supply, and connecting each electrode in the first layer cathode electrode group 201 with the negative electrode of the direct current power supply; meanwhile, each electrode in the first layer of anode electrode group 101 is connected with a suction pipeline 4 connected with a vacuum negative pressure source, and each electrode in the first layer of cathode electrode group 201 is communicated with the atmosphere, so that hydrogen generated by the cathode is released, and the phenomenon that the hydrogen is absorbed by the negative pressure and migrates to the anode to be mixed with chlorine and explode is prevented; starting a power supply and a vacuum negative pressure source, and simultaneously performing negative pressure dehydration and electric dechlorination on the first slurry layer 31 according to the designed and given electric field parameters (voltage value or current value, constant power supply or intermittent power supply) and the designed and given negative supply pressure parameters (negative pressure value, constant negative pressure or intermittent negative pressure);

under the common total use of the electric field and the negative pressure, chloride ions migrate to the anode and are discharged from the anode; because the electromigration rate of calcium ions is far higher than the liquid flow migration rate, and the migration state of the calcium ions can be controlled by adjusting the electric field parameters and the negative pressure parameters, the calcium ions are driven by the electric field to migrate to the cathode by countercurrent flow, and because the cathode has no outlet, the calcium ions are left in the slag slurry; simultaneously, water in the slurry is discharged from the anode under the negative pressure drive; the technical effect of dewatering and dechlorinating simultaneously is realized;

during the period, the slag slurry is continuously injected until a second slag slurry layer 32 is formed, a second anode electrode group 102 is laid on the second slag slurry layer 32, the slag slurry is injected again on the second anode electrode group 102 to form a third slag slurry layer 33, and the operation of the sixth step can be carried out after the thickness of the injected slag slurry meets the requirement of protecting the electrode group;

and a sixth step: connecting each electrode in the second anode electrode group 102 with the anode of the direct current power supply; simultaneously connecting each electrode in the second layer anode electrode group 102 to a suction pipeline 4 connected with a vacuum negative pressure source, starting the vacuum negative pressure source, applying voltage and negative pressure to the second slurry layer 32 according to the designed and given electric field parameters and the designed and given negative pressure supply parameters, and simultaneously performing negative pressure dehydration and electric dechlorination on the second slurry layer 32;

during the period, the caustic sludge slurry is continuously injected until a third slurry layer 33 is formed, a second layer cathode electrode group 202 is laid on the third slurry layer 33, and the caustic sludge slurry is injected again on the second layer cathode electrode group 202 to form a fourth slurry layer 34, but after the thickness of the injected caustic sludge slurry meets the requirement of protecting the electrode group, the seventh step can be carried out;

the seventh step: connecting each electrode in the second layer of cathode electrode group 202 with the negative electrode of the direct current power supply; the third slurry layer 33 is simultaneously subjected to negative pressure dehydration and electric dechlorination;

during the period, the slag slurry is continuously injected until a fourth slag slurry layer 34 is formed, a third layer of anode electrode group 103 is laid on the fourth slag slurry layer 34, the slag slurry is injected again on the third layer of anode electrode group 103 to form a fifth slag slurry layer, but the eighth step of work can be carried out after the thickness of the injected slag slurry meets the requirement of protecting the electrode group;

eighth step: repeating the operation according to the procedures and methods in the sixth step to the seventh step, finishing the laying of the anode electrode group 1 and the cathode electrode group 2 of each layer on the pile layer by layer, and finishing the piling and chlorine removal and dehydration work of each slag slurry layer 3 on the pile layer until the designed given pile height is reached;

the ninth step: when the chlorine removal and dehydration of the slurry in the first slurry layer 31 reach the designed given index value, the connection between the first layer of anode electrode group 101 and the power supply is cut off, and the application of the negative pressure is stopped; when the chlorine removal and dehydration of the slurry in the second slurry layer 32 reach the designed index value, the connection between the first cathode electrode group 201 and the power supply can be cut off, the connection between the anode electrode group 1 or the cathode electrode group 2 and the power supply can be cut off layer by layer for each layer of slurry on the second slurry layer according to the requirements and the method, the application of negative pressure is stopped, and the chlorine removal and dehydration work of all layers of slurry is finally completed.

The slag slurry is discharged as CaCO in the process of producing soda ash₃The main component is waste residue slurry containing chlorine salt; also includes other industrial discharged CaCO₃The main component is waste residue slurry containing chlorine salt.

The anode electrode may be a well-known commercially available conductive plastic drain plate, and preferably, the anode electrode is a simultaneous co-pressure water absorption electrode capable of applying negative pressure water absorption over the entire length thereof at the simultaneous co-pressure. The known conductive plastic drainage plate is a series negative pressure drainage method; when negative pressure with a certain pressure value is applied to one end of the conductive plastic drainage plate, the negative pressure in the drainage belt is smaller and smaller along with the increase of the length from the negative pressure application end due to the fact that gas and liquid in the alkaline residue slurry migrate into the drainage belt and gradually offset the negative pressure; therefore, the negative pressure value is not uniform in the whole length range of the drainage belt, which causes different drainage effects of all parts in the caustic sludge slurry. The synchronous water-absorbing electrode of the invention has the advantages that the negative pressure in the main water pipe which is long is basically consistent, and the negative pressure values output by each point on the electrode are basically the same, so that the water discharging effect in the full-length range of the synchronous water-absorbing electrode is basically uniform.

As shown in fig. 6 and 7, for the vertically used electrode, the vertically synchronous co-pressure water absorption electrode which can make liquid pass through and can apply negative pressure water absorption in the whole length range thereof at the synchronous co-pressure comprises a suction pipe 10, a water guide pipe 11 and a strip 12; the suction pipe 10 is arranged in the aqueduct 11, two ends of the aqueduct 11 are closed, a gap of 1mm-10cm is left between the lower end of the suction pipe 10 and the bottom end surface of the aqueduct 11, or the lower end of the suction pipe 10 is connected with the bottom end of the aqueduct 11 but a hole is left at the lower end of the suction pipe 10 to ensure that water flows between the suction pipe and the aqueduct 11; the upper end of the suction pipe 10 penetrates through the top end face of the water guide pipe 11 and is connected with a suction pipeline 4 communicated with the fluid extraction device, and the pipe wall of the suction pipe 10 penetrating through the top end face of the water guide pipe 11 is hermetically sealed with the top end face of the water guide pipe 11; the aqueduct 11 can be a conductive or non-conductive plastic pipe, the diameter or the short side size of which is 0.5 cm-10 cm; the pipe walls at two sides of the water guide pipe 11 are respectively provided with a plurality of water outlet holes 110 which are regularly arranged; the pipe walls of the two sides are respectively connected with a strip 12, the strip 12 can be made of conductive materials, preferably a conductive plastic strip, the cross section of the strip parallel to the water guide pipe 11 is a series of parallel H-shaped grooves, and the ports of the upper and lower two grooves of each H-shape on one side of the strip 12 are communicated with a water outlet 110 on the pipe wall of the water guide pipe 11; the minimum side length of the groove is 1mm to 50 mm; the series of juxtaposed grooves on the strip 12 may also be other than H-shaped grooves, and may take any feasible form; the outer surfaces of the two strips 12 are coated with a filter layer.

As shown in fig. 8, for the vertically used electrode, the vertically water-permeable electrode is a vertically water-permeable electrode which can allow liquid to pass through and can simultaneously exert negative pressure and absorb water in the whole length range, the vertically water-permeable electrode comprises an outer tube 14 and an inner tube 15, the tube wall of the outer tube is provided with a plurality of micropores 140, and the outer tube 14 is made of a conductive material; the inner pipe 15 is made of a non-conductive material, the inner pipe 15 is arranged in the outer pipe 14 through a positioning frame, the top end of the outer pipe 14 is closed, and the bottom end of the outer pipe 14 is closed; a gap 142 is reserved between the bottom end of the inner pipe 15 and the bottom end of the outer pipe 14, and an inner pipe water outlet 151 is formed in the top end of the inner pipe 15; the water outlet 151 of the inner tube penetrates through the top end of the outer tube 14; the outer surface of the outer tube 14 is coated with a filter layer, which is a special case that the width of the strip 12 of the vertical synchronous simultaneous-pressure water-absorbing electrode is 0.

As shown in fig. 9 and 10, for the horizontally used electrode, the horizontal synchronous co-pressure water absorption electrode which can make liquid pass through and can apply negative pressure water absorption in the whole length range thereof with synchronous co-pressure comprises a water guide pipeline 11 and a strip 12; the water guide pipeline 11 is a conductive or non-conductive plastic pipe, and the diameter or the short side size of the water guide pipeline is 0.5 cm-10 cm; the pipe walls at two sides of the water guide pipeline 11 are respectively provided with a plurality of regularly arranged water outlet holes 110; the pipe walls of the two sides are respectively connected with a strip 12, the strip 12 can be made of conductive materials, preferably a conductive plastic strip, the cross section of the strip parallel to the water guide pipe 11 is a series of parallel H-shaped grooves 121, and the ports of the upper and lower H-shaped grooves 121 on one side of the strip 12 are communicated with a water outlet hole 110 on the pipe wall of the water guide pipe 11; the minimum side length of the groove 121 is 1mm to 50 mm; the series of juxtaposed grooves on the strip 12 may also be other than H-shaped grooves, and may take any feasible form; the outer surfaces of the two strips 12 are coated with a filter layer.

The anode electrode which can make liquid pass through and can apply negative pressure water absorption in the whole length range of the anode electrode by synchronous and simultaneous pressure can also be a conductive material tube with a plurality of micropores on the tube wall, and the outer surface of the conductive material tube is coated with a filter layer.

The cathode electrode can be an electrode which can conduct electricity and can pass water, and the cathode electrode can be tubular or plate-shaped or strip-shaped. The conductive material in the anode and cathode may be any of various known conductive materials, preferably a conductive polymer. The cathode electrode and the anode electrode may be made of different materials and structures.

One end or two ends of each anode electrode in each anode electrode group are connected with at least one drainage branch pipe; one end or two ends of each cathode electrode in each cathode electrode group are connected with at least one drainage branch pipe; and the water injection and drainage branch pipes connected with the anode electrodes in the anode electrode group penetrate through the slag slurry retaining body through the flexible pipes and are connected with the suction pipeline 4. And the water drainage branch pipes connected with the cathode electrodes in the cathode electrode group are connected with the atmosphere after penetrating through the slag slurry surrounding baffle body through the flexible pipes.

As shown in fig. 11, the gas-liquid separation system includes a liquid reservoir device 51, a vacuum negative pressure source 52, and a gas pressure reduction tank device 53; one end of the suction pipeline 4 is connected to the liquid storage tank device 51, a first liquid level sensor 511 is arranged on the liquid storage tank device 51, a first liquid pump suction pipeline 512 is arranged at the bottom of the liquid storage tank device 51, the height of liquid deposited in the liquid storage tank 51 is detected through the first liquid level sensor 511, and the first liquid pump suction pipeline 512 is controlled to pump out the liquid to be conveyed to the liquid storage tank. The liquid storage tank device 51 is connected with the air inlet end of the vacuum negative pressure source 52 through a first connecting pipe, and the air outlet end of the vacuum negative pressure source 52 is connected with the gas pressure reduction tank device 53 through a second connecting pipe; a plurality of spraying pipes 533 are arranged at the upper part of the gas pressure reduction tank 53, and the liquid inlet ends of the spraying pipes 533 are communicated with the liquid supply pool; the liquid outlet end of the spraying pipe 533 is provided with a spraying head for spraying the liquid absorbing chlorine in a liquid mist state, so that the chlorine in the gas injected from the air outlet end of the vacuum negative pressure source 52 through the second connecting pipe can be better absorbed. The gas treated by the liquid mist is gathered at the top of the gas pressure reduction tank 53, the top of the gas pressure reduction tank 53 is also provided with a chlorine absorption pipeline 534, and the chlorine absorption pipeline 534 is respectively connected with the atmosphere and a chlorine absorption device; an atmosphere switch 535 and a chlorine absorption switch 536 are respectively arranged on the chlorine absorption pipeline 534; if the concentration of chlorine in the gas after the liquid mist treatment meets the emission limit of the national environmental protection standard, opening an atmosphere switch 535 and discharging the gas to the atmosphere; if the concentration of chlorine in the mist-treated gas does not meet the emission limit of the national environmental standard, the chlorine absorption switch 536 is turned on, and the gas is transported to a subsequent disposal device through the chlorine absorption pipeline 534.

The gas pressure reduction tank 53 is provided with a second liquid level sensor 531, the bottom of the gas pressure reduction tank 53 is provided with a second liquid pump discharge pipeline 532, the liquid height of the liquid deposited on the lower part of the gas pressure reduction tank 53 after the liquid mist absorbs chlorine is detected through the second liquid level sensor 531, and the second liquid pump discharge pipeline 532 is controlled to convey the liquid to the liquid storage pool.

Because the anode is communicated with the vacuum negative pressure source and is in a basically anhydrous state, chlorine is generated after chloride ions driven to the anode by the electric field are contacted with the exposed conductor in the anode; the gas-liquid mixture containing chlorine is drawn by the vacuum negative pressure source 52 and is input into a gas-liquid separation system connected with the suction pipeline 4 through the suction pipeline 4, and the liquid in the gas-liquid separation system is deposited at the lower part of the liquid storage tank device 51, is pumped by a liquid pump through a first liquid pump pumping pipeline 512 and is discharged into a liquid storage tank; the gas therein is discharged into a gas decompression tank device 53 through a vacuum negative pressure source 52; then, according to specific situations, the following measures are respectively adopted:

firstly, if less chloride ions enter the anode, less chlorine gas is generated; or more alkaline residue slurry (the pH value of the alkaline residue slurry is usually between 9 and 11) enters the anode, and less residual chlorine is absorbed by the alkaline residue slurry; in this case, chlorine gas does not exceed the limits of the national environmental standards; the gas entering the gas pressure reduction tank device 53 can be discharged directly to the atmosphere as if the gas pressure reduction tank 53 were absent, the gas being discharged directly to the atmosphere by the vacuum negative pressure source;

if the gas entering the gas pressure reduction tank device 53 has high chlorine content and cannot be directly discharged to the atmosphere, the spraying pipe 533 positioned at the upper part of the gas pressure reduction tank device 53 is opened, known liquid for absorbing chlorine, such as sodium hydroxide solution, is sprayed, the liquid for absorbing chlorine is deposited at the bottom of the gas pressure reduction tank device 53 and is pumped out by the second liquid pump exhaust pipe 532 and is discharged into the liquid storage tank; the gas which meets the emission standard and is treated by chlorine absorption is discharged to the atmosphere;

thirdly, if less alkaline residue slurry enters the anode and more chloride ions enter the anode, more chlorine gas is generated; after the treatment by the method, the chlorine content in the gas still exceeds the emission limit of the national atmosphere environmental protection standard, the gas is pumped out from the top of the gas decompression tank device 53 by adopting a gas pump and is treated according to the known chlorine absorption method.

According to the matching relation of the water content and the chlorine content of the slurry, the electric field parameters and the negative pressure parameters, the slurry of each layer can a) remove chlorine and dehydrate at the same time; b) the water content reaches the design index firstly; c) the chlorine removal amount firstly reaches the design requirement;

meanwhile, if the water content and the dechlorination amount in the first slag slurry layer 31 simultaneously meet the design requirements, the suction pipeline 4 connecting the first layer of anode electrode group 101 with the vacuum negative pressure source is closed and disconnected with the power supply; the first anode electrode group 101 may be connected to the atmosphere;

if the water content in the first slag slurry layer 31 is reduced to the index specified by the design but the chlorine content does not meet the design requirement, the dehydration work of the alkaline slag slurry layer is stopped, one end of each electrode in the first anode electrode group 101 is connected to a branch pipe communicated with the injection pipeline, and the other end of each electrode in the first anode electrode group 101 is connected to a branch pipe communicated with the suction pipeline; injecting a liquid which is designed and given to absorb chlorine into each electrode in the anode electrode group 1 through an injection branch pipe communicated with the injection pipeline according to the designed and given flow rate, and continuing to perform the electric dechlorination work of the first slag slurry layer 31; until the chlorine content in the first slag slurry layer 31 is reduced to a design index, closing the connection between the first layer of anode electrode group 101 and the injection pipeline and the suction branch pipe, and disconnecting the anode electrode group from the power supply; the first anode electrode group 101 may be connected to the atmosphere;

if the chlorine content in the first slurry layer 31 is reduced to the index specified by the design but the water content does not meet the design requirement, disconnecting the first layer of anode electrode group 101 from the power supply, keeping the first layer of anode electrode group 101 and the first layer of cathode electrode group 201 connected to the suction pipeline 4 connected with the vacuum negative pressure source, performing negative pressure dehydration on the first slurry layer 31 according to the negative pressure supply parameters given by the design until the water content and the dechlorination amount in the first slurry layer 31 meet the design requirement, and closing the pipeline 4 connected with the vacuum negative pressure source by the first layer of anode electrode group 101; the first anode electrode group 101 may be connected to the atmosphere;

if the water content and the dechlorination amount in the second slag slurry layer 32 and the third slag slurry layer 33 simultaneously meet the design requirements, disconnecting the first layer of cathode electrode group 201 and the second layer of anode electrode group 102 from the power supply; the suction pipeline 4 of the second layer of anode electrode group 102 connected with the vacuum negative pressure source is closed, and the first layer of cathode electrode group 201 and the second layer of anode electrode group 102 can be communicated with the atmosphere;

if the water content in the second slag slurry layer 32 and the third slag slurry layer 33 is reduced to the index specified by the design but the chlorine content does not meet the design requirement, the dehydration work of the two layers of alkaline slag slurry is stopped, one end of each electrode in the second anode electrode group 201 is connected to a branch pipe communicated with the injection pipeline, and the other end of each electrode in the second anode electrode group 102 is connected to a branch pipe communicated with the suction pipeline; injecting a liquid which is designed to absorb chlorine into each electrode in the second layer of anode electrode group 102 through a branch pipe communicated with an injection pipeline according to the designed given flow; until the chlorine content in the second slag slurry layer 32 and the third slag slurry layer 33 is reduced to the design index, the connection between the second layer anode electrode group 102 and the injection pipeline and the suction pipeline is closed, and the second layer anode electrode group 102 and the first layer cathode electrode group 201 are disconnected from the power supply; the second layer anode electrode group 102 and the first layer cathode electrode group 201 can be communicated with the atmosphere;

if the chlorine content in the second slag slurry layer 32 and the third slag slurry layer 33 is reduced to the index specified by the design but the water content does not meet the design requirement, disconnecting the second layer anode electrode group 102 and the first layer cathode electrode group 201 from the power supply, connecting the second layer anode electrode group 201, the first layer cathode electrode group 201 and the second layer cathode electrode group 202 to the suction pipeline 4 connected with the vacuum negative pressure source, performing negative pressure dehydration on the second slag slurry layer 32 and the third slag slurry layer 33 according to the negative pressure value given by the design, and closing the suction pipeline 4 connected with the vacuum source by the second layer anode electrode group 102, the first layer cathode electrode group 201 and the second layer cathode electrode group 202 when the water content and the chlorine removal amount in the second slag slurry layer 32 and the third slag slurry layer 33 meet the design requirement; the second anode electrode group 102 and the first cathode electrode group 201 can be communicated with the atmosphere;

when the water content and the dechlorination amount in the fourth slag slurry layer 34 and the fifth slag slurry layer 35 simultaneously reach the design requirements, closing the suction pipeline 4 for connecting the third layer anode electrode group 103 with the vacuum negative pressure source, and disconnecting the third layer anode electrode group 103 and the second layer cathode electrode group 202 from the power supply; the third layer of anode electrode group 103 and the second layer of cathode electrode group 202 can be communicated with the atmosphere;

if the water content in the fourth slag slurry layer 34 and the fifth slag slurry layer is reduced to the index specified by the design but the chlorine content does not meet the design requirement, stopping the dehydration work of the two layers of alkaline slag slurry, connecting one end of each electrode in the third layer of anode electrode group 103 to a branch pipe communicated with the injection pipeline, and connecting the other end of each electrode in the third layer of anode electrode group 103 to a branch pipe communicated with the suction pipeline; injecting a designed and given liquid for absorbing chlorine into each electrode in the third layer anode electrode group 103 through a branch pipe communicated with the injection pipeline according to a designed and given flow rate; until the chlorine content in the fourth slag slurry layer 34 and the fifth slag slurry layer is reduced to the design index, the connection between the third layer anode electrode group 103 and the injection pipeline and the suction pipeline is closed, and the third layer anode electrode group 103 and the second layer cathode electrode group 202 are disconnected with the power supply; the third anode electrode set 103 and the second cathode electrode set 202 may be vented to atmosphere;

if the chlorine content in the fourth slag slurry layer 34 and the fifth slag slurry layer is reduced to the index specified by the design but the water content does not meet the design requirement, disconnecting the third layer anode electrode group 103 and the second layer cathode electrode group 202 from the power supply, connecting the third layer anode electrode group 103, the second layer cathode electrode group 202 and the third layer cathode electrode group to the suction pipeline 4 connected with the vacuum negative pressure source, performing negative pressure dehydration on the second slag slurry layer 32 and the third slag slurry layer 33 according to the designed given negative pressure value, and closing the suction pipeline 4 connected with the vacuum negative pressure source by the third layer anode electrode group 103, the second layer cathode electrode group 202 and the third layer cathode electrode group when the water content and the chlorine removal amount in the fourth slag slurry layer 34 and the fifth slag slurry layer reach the design requirement; the third anode electrode set 103 and the second cathode electrode set 202 can be connected to the atmosphere;

and (3) stopping the electric dechlorination and dehydration work of each layer by layer according to the rule and the method respectively aiming at the three conditions by measuring the concentration of the chloride ions in the discharged liquid of each anode layer and the water yield or measuring the concentration and the water content of the chloride ions in the drilled samples of each slurry layer. Not only the dechlorination and the dehydration of the whole slag pulp piling body are completed.

Examples

The caustic sludge slurry discharged in the production process of the caustic plant comprises 66.4% of calcium carbonate, 9.8% of calcium chloride, 4.9% of sodium chloride and 268% of water content; permeability coefficient 1.15X 10^-6cm/s; the pH value is 11.6.

Target value: the chloride ions are removed by 95 percent, and the water content is reduced to 100 percent. Dechlorination is intended as an industrial feedstock and it is therefore desirable to retain as much calcium as possible.

According to the injection rate of the waste residue slurry of the alkali factory, on the basis that the time for injecting a layer of alkali residue slurry is matched with the time for dechlorinating and dewatering a layer of alkali residue slurry and the stacking rate of the alkali residue slurry can ensure the stability of the stacking body of the alkali residue slurry, a stacking site is taken to be 25m wide, 30m long and 25m stacked.

The synchronous water absorption electrode 10 shown in fig. 5 and 6 is selected as an electrode; the water guide pipeline 11 is a plastic pipe, 2cm in width and 1cm in height; the pipe walls at two sides of the water outlet pipe are respectively provided with a plurality of water outlet holes 110 which are regularly arranged; the pipe walls of the two sides are respectively connected with a conductive plastic strip 12, the section of the conductive plastic strip parallel to the water guide pipe 11 is a series of parallel H-shaped grooves, the width of each strip 12 at the two sides is 8cm, the height and the width of a single groove on each H-shaped groove are both 2mm, and the ports of the upper and lower grooves 121 of each H-shape at one side of each strip 62 are communicated with a water outlet hole 110 on the pipe wall of the water guide pipe 11; the outer surfaces of the two strips 12 are coated with a filter layer.

The method comprises the following steps as shown in figures 1-4:

1. piling a cofferdam at the periphery of a site where waste residue slurry is to be piled, wherein the initial height of the cofferdam is 1 m; then the height of the slurry is increased gradually along with the injection of the caustic sludge slurry; pouring alkaline residue slurry into the cofferdam to form a thin cushion layer of 10cm, arranging synchronous homogeneous water-absorbing electrodes on the thin cushion layer in parallel with the short edge of the cofferdam at a distance of 100cm in parallel and horizontally to form a first layer of anode electrode group 101, pouring the residue slurry into the first layer of anode electrode group 101 until the height of the residue slurry reaches 1m to form a first residue slurry layer 31, and arranging cathode electrodes on the first residue slurry layer 31 in parallel with the short edge of the cofferdam at a distance of 100cm in parallel and horizontally to form a first layer of cathode electrode group 201; connecting each electrode in the first layer anode electrode group 101 with the positive electrode of a direct current power supply, and connecting each electrode in the first layer cathode electrode group 201 with the negative electrode of the direct current power supply; meanwhile, two ends of each electrode in the first layer of anode electrode group 101 are connected to a suction pipeline 4 communicated with a vacuum negative pressure source, and each electrode in the first layer of cathode electrode group 201 is communicated with the atmosphere; paving the alkaline residue slurry on the cathode electrode group 201 to form a second slurry layer 32; when the paving thickness of the layer of alkaline residue slurry can form a protection condition for the first layer of cathode electrode group 201 below the alkaline residue slurry, the following work 2 can be carried out;

2. switching on a power supply for the first layer of anode electrode group 101 and the first layer of cathode electrode group 201, applying 40V direct current voltage according to a power supply mode of switching on for 45 minutes and stopping for 15 minutes, and applying an electric field to the first slag slurry layer 31; simultaneously, starting a vacuum negative pressure source to apply negative pressure to the first slag slurry layer 31 through the suction pipeline 4 at a negative pressure value of which the vacuum degree is not lower than 80; starting the dechlorination and dehydration of the first slag slurry layer 31; the uniform electric field formed in the first slag slurry layer 31 drives chloride ions in the alkaline slag slurry to migrate to the first layer of anode electrode group 101, and the chloride ions are pumped out by the vacuum negative pressure source through the suction pipeline 4 along with moisture in the alkaline slag slurry; the calcium ions migrate to the first layer of cathode electrode assembly 201 under the action of the electric field, and are retained in the waste slag because no outlet exists in the direction; meanwhile, the water in the alkaline residue slurry is pumped out from the anode electrode group 101 through the suction pipeline 4 by a vacuum negative pressure source under the negative pressure drive and is discharged; thereby realizing the technical effects of dewatering the alkaline residue slurry and removing chloride ions out of the alkaline residue slurry while retaining calcium ions;

continuously piling up a cofferdam to 2m, then continuously piling up alkaline residue slurry in the cofferdam until the thickness of the slurry layer reaches 1m to form a second slurry layer 32, and arranging a second layer of anode electrode group 102 on the second slurry layer 32; the second layer of anode electrode assembly 102 is continuously piled with alkaline residue slurry to form a third slurry layer 33, but when the paving height of the slurry layer can form a protection condition for the second layer of anode electrode assembly 102 below the slurry layer, the following work 3 can be carried out;

3. connecting each electrode in the second layer anode electrode group 102 on the top surface of the second slag slurry layer 32 with the positive electrode of the direct current power supply, and simultaneously connecting two ends of each electrode in the second layer anode electrode group 102 with the suction pipeline 4 connected with the vacuum negative pressure source; applying an electric field to the second slurry layer 32 by turning on the power supply as required by 2; simultaneously, applying negative pressure to the second slag slurry layer 32 according to the requirement of 2 to perform the dechlorination and dehydration work of the second slag slurry layer 32; the uniform electric field formed in the second slag slurry layer 32 drives chloride ions in the alkaline slag slurry to migrate to the second layer anode electrode group 102 and be pumped out by the vacuum negative pressure source through the suction pipeline 4 along with moisture in the alkaline slag slurry; the calcium ions migrate to the first layer of cathode electrode assembly 201 under the action of the electric field, and are retained in the waste slag because no outlet exists in the direction; meanwhile, the water in the alkaline residue slurry is pumped out from the anode electrode group 101 through the suction pipeline 4 by a vacuum negative pressure source under the negative pressure drive and is discharged; thereby realizing the technical effects of dewatering the alkaline residue slurry and removing chloride ions out of the alkaline residue slurry while retaining calcium ions;

meanwhile, if the concentration and the water content of the chloride ions in the first slag slurry layer 31 are reduced to design given indexes, the first layer of the anode electrode group 101 is disconnected from the power supply, and the suction pipeline 4 for communicating each electrode of the first layer of the anode electrode group 101 with the vacuum negative pressure source is disconnected;

meanwhile, the cofferdam can be continuously piled up to 3m, then the caustic sludge slurry is continuously piled up in the cofferdam until the thickness of the slurry layer reaches 1m, a third slurry layer 33 is formed, and a second cathode electrode group 202 is arranged on the third slurry layer 33; the caustic sludge slurry is continuously piled on the second cathode electrode group 202 layer to form a fourth slurry layer 34, but when the paving thickness of the caustic sludge slurry layer can form a protection condition for the second cathode electrode group 202 layer below the caustic sludge slurry layer, the following 4 operations can be carried out;

4. connecting the second layer cathode electrode group 202 on the top surface of the third slag slurry layer 33 to the negative electrode of the direct current power supply, and communicating each electrode on the cathode electrode group 2 with the atmosphere; applying an electric field and negative pressure to the third slurry layer 33 according to the requirement 2; the uniform electric field formed in the third slag slurry layer 33 drives chloride ions in the alkaline slag slurry to migrate to the anode electrode and be pumped out by the vacuum negative pressure source through the suction pipeline 4 along with moisture in the alkaline slag slurry; the calcium ions migrate to the second layer cathode electrode group 202 under the action of the electric field and are retained in the waste residues because no outlet exists in the direction, so that the technical effects of dewatering the alkaline residue slurry and removing chloride ions from the waste residues to retain the calcium ions are achieved;

when the concentration and the water content of the chloride ions in the second slag slurry layer 32 are reduced to design given indexes, the first layer cathode electrode group 201 is disconnected with a power supply;

meanwhile, the cofferdam can be continuously piled up to 4m, then the caustic sludge slurry is continuously piled up in the enclosing and blocking body until the thickness of the slurry layer reaches 1m, a fourth slurry layer 34 is formed, and a third layer of anode electrode group 103 is arranged on the fourth slurry layer 34; continuously stacking alkaline residue slurry on the third layer of anode electrode group 103 to form a fifth residue slurry layer, wherein when the stacking thickness of the alkaline residue slurry layer can form a protection condition for the third layer of anode electrode group 103 below the alkaline residue slurry layer, the following work of 5 can be performed;

5. repeating the operation according to the procedures and methods of 3) -4), finishing the laying of the anode electrode group 1 and the cathode electrode group 2 of each layer on the pile layer by layer, finishing the piling and chlorine removal and dehydration work of each slurry layer 3 on the pile layer by layer until the designed given pile height is reached;

6. the gas-liquid mixture drawn out by the vacuum negative pressure source through the suction pipe 4 passes through a gas-liquid separator shown in fig. 3, which is located on the suction pipe 4, to form gas-liquid separation, wherein the liquid part is deposited at the lower part of the gas-liquid separator; the gas-liquid separator is provided with a known liquid level sensor which controls the liquid pump to pump out deposited liquid at any time and collect the liquid in the liquid storage pool; the gas part is pumped out by a vacuum negative pressure source 52 and is conveyed to a gas decompression tank device 53, and the chlorine in the gas exceeds the standard and cannot be directly discharged to the atmosphere; the gas input from the vacuum negative pressure source 52 is input from the middle lower part of the gas pressure reducing tank device 53, the upper part of the gas pressure reducing tank device is provided with a liquid spraying nozzle, liquid mist containing 15 percent NaCl is sprayed out of the liquid spraying nozzle, the NaCl liquid mist absorbs chlorine to form sodium hypochlorite to be deposited on the lower part of the gas pressure reducing tank device 53, the lower part of the gas pressure reducing tank device 53 is provided with a known liquid level sensor, and the liquid level sensor controls a liquid pump to pump out the deposited liquid at any time and collect the liquid in a liquid storage pool; and the dechlorinated gas meeting the national environmental protection standard is discharged into the atmosphere from an exhaust pipe at the top of the gas pressure reduction tank device.

The method can also be used for carrying out in-situ dechlorination and dehydration treatment on the large-quantity stock caustic sludge slurry.

The caustic sludge slurry discharged from the caustic plant is usually stored in a slurry warehouse similar to a reservoir, thousands of high-moisture-content caustic sludge slurry stocks are formed after years of accumulation, and the caustic sludge slurry belongs to secondary solid waste specified by the state, so that the relevant environmental protection standard of the state is specified, and the caustic sludge slurry is not subjected to harmless treatment and is not transferred. The invention can be used for carrying out in-situ dechlorination and dehydration treatment on the alkali residue slurry in the waste closed alkali residue slurry warehouse.

By using a construction method of vacuum preloading of geotechnical engineering, vertically implanting the synchronous and synchronous water absorption electrodes or the commercially available conductive drainage strips into the alkaline residue slurry according to a given arrangement mode, spacing and depth; simultaneously connecting a synchronous same-pressure water absorption electrode or a conductive water drainage belt (anode electrode for short) connected to the positive electrode of a direct-current power supply to a suction pipeline communicated with a vacuum negative pressure source; connecting a synchronous and same-pressure water absorption electrode or a conductive water drainage belt (cathode electrode for short) connected to the negative electrode of a direct-current power supply to an exhaust pipeline communicated with the atmosphere; and a sealing film (plastic film) is paved on the surface of the alkaline residue slurry to isolate the system from the outside atmosphere. There must be one cathode electrode around each anode electrode and one anode electrode around each cathode electrode.

Applying an electric field to the caustic sludge slurry through an electrode according to a designed and given power supply mode, starting a vacuum negative pressure source at a designed and given time, and applying negative pressure to the caustic sludge slurry according to a designed and given negative pressure value and a negative pressure supply mode; and carrying out negative pressure dehydration and electric dechlorination on the layer of alkaline residue slurry simultaneously.

Under the combined action of an electric field and negative pressure, chloride ions in the alkaline residue slurry migrate to the anode electrode, and water in the alkaline residue slurry migrated to the anode electrode is discharged from a suction pipeline connected with a vacuum negative pressure source; because the electromigration rate of calcium ions is far higher than the liquid flow migration rate, and the migration state of the calcium ions can be controlled by adjusting the electric field parameters and the negative pressure parameters, the calcium ions are driven by the electric field to migrate to the cathode by countercurrent flow, and because the cathode has no outlet, the calcium ions are left in the caustic sludge slurry; meanwhile, water in the alkaline residue slurry is driven by negative pressure to migrate to the anode and is discharged from the suction pipeline; the technical effect of dewatering and dechlorinating simultaneously is realized;

the gas-liquid mixture containing the chlorine is drawn by the negative pressure source and is discharged through the suction pipeline; the liquid is deposited in the liquid storage tank device 51 and pumped out by the liquid pump through the gas-liquid separation system arranged on the pumping pipeline 4; the gas is discharged from the vacuum negative pressure source 52 into the gas pressure reducing tank device 53, and is subjected to chlorine absorption treatment.

When the concentration and the water content of chloride ions in the alkaline residue slurry reach design given indexes, the direct-current power supply and the vacuum negative pressure source can be closed; thus completing the dechlorination and dehydration of the caustic sludge slurry layer. The alkaline residue slurry on the layer which is subjected to dechlorination and dehydration is dug out and can be used as a raw material for resource utilization. According to the operation, the next layer of alkali residue slurry can be subjected to dechlorination and dehydration. The chlorine removal and dehydration work of all the alkaline residue slurry in the alkaline residue slurry storage can be finished by the layer-by-layer treatment.

Compared with the prior art, the invention has the beneficial effects that:

(1) the dechlorination and dehydration technology which is suitable for the large-volume caustic sludge slurry and has low cost is constructed. The current situation that no economical and effective dechlorination dehydration method exists in large quantity is ended. Creates conditions for the resource utilization of the caustic sludge slurry.

(2) Harmful ions can be selected to remove harmful substances in the alkaline residue slurry, and beneficial ions are reserved; thereby reducing the total amount of substances to be removed and improving the removal efficiency; meanwhile, more beneficial substances can be reserved, and the resource utilization rate of waste residues is improved.

(3) The technology solves the technical obstacle encountered when the electric technology is used for removing the dirt of the specific substance of the caustic sludge slurry, namely harmful chlorine generated at the anode pollutes the environment.

(4) The technology can be used for dechlorinating and dehydrating the alkali residue slurry at low cost, not only can greatly reduce the stacking volume of the waste alkali residue slurry, but also can reduce the occupied land of a waste residue storage yard, and the alkali residue slurry after dechlorinating and dehydrating can be recycled as an industrial raw material.